For the past few months my computer has been crashing it is normally while Playing LoL and now that i tried playing minecraft, minecraft i believe it to be overheating but i'm not sure.

What happens is that the screen will go black and say no connection like it isn't connected to my computer at all if i'm on Skype i can still talk for a little while before it just blacks out i'm assuming it might be a safety feature in my graphics card when it get's to hot but i'm not sure.

If you think its heat, I would open case and check for unusual amounts of dust. Maybe blow out the card and the case. If its a graphics card, you will need to borrow another card and swap it out to test, ask a buddy. I would think that the 570 could handle what your playing, but if not maybe turn down the settings and try that. There are several GPU stress testers out there, try here,EVGA | Support | EVGA Software

they have several useful programs that may give you info on your problem. You have to join
but I find them useful.

Thanks for the help i'm getting a proper cpu cooler instead of the standard so maybe that will help but with the whole if my graphics card is good enough to run the games it is as i can run BF3 and other games on ultra fine without crashing but it just seems to be LoL which is the real killer i was just playing Supreme commander: forged alliance for 4 hours with no crashing but i couldn't do that with LoL.